body{
    margin: 0;
    padding: 0;
}

.positioner{
    margin: 0 auto;
    position: relative;
    top: 50px;
    width: 850px;
    height: 500px;

    border: 1px solid black;
}

h1{
    text-align: center;
    font-size: 30px;
    font-weight: 500;
}

.gameArea{
    float: left;
    height: 333px; /* 75*4 + 5*5 + 8*1 */
    width: 333px; 
    font-size: 0; /* 去除inline-block间隙 */
    margin-left: 50px;
    margin-bottom: 20px;
}

.gameArea div div{
    background-image: url('res/0.jpg');
    background-size: 400%;
    background-repeat: no-repeat;

    font-size: 1rem;
    color: rgb(29, 29, 29);
}
.row1 .block{
    margin-top: 5px;
}

.block{
    display: inline-block;
    height: 75px;
    width: 75px;
    margin-left: 5px;
    margin-bottom: 5px;
    border: 1px solid rgb(175, 175, 175);

    text-align: center;
    line-height: 75px;
    transition: 0.2s;

    background-size: 300px 300px;
}
.without{
    display: none;
}

#block1{   
    background-position: 0 0;
}
#block2{
    background-position: -75px 0;
}
#block3{
    background-position: -150px 0;
}
#block4{
    background-position: -225px 0;
}

#block5{
    background-position: 0 -75px;
}
#block6{
    background-position: -75px -75px;
}
#block7{
    background-position: -150px -75px;
}
#block8{
    background-position: -225px -75px;
}

#block9{
    background-position: 0 -150px;
}
#block10{
    background-position: -75px -150px;
}
#block11{
    background-position: -150px -150px;
}
#block12{
    background-position: -225px -150px;
}

#block13{
    background-position: 0 -225px;
}
#block14{
    background-position: -75px -225px;
}
#block15{
    background-position: -150px -225px;
}

.gameImg{
    margin-right: 50px;
    margin-bottom: 20px;
    float: right;
}
.gameImg img{
    border: 1px solid black;
    height: 333px;
    width: 333px;
}

.footer{
    clear: both;
    text-align: center;
}

.footer button{
    color: white;
    background-image: linear-gradient(to bottom, rgb(100, 136, 255), rgb(64, 76, 180));
    margin: 0 10px;
    height: 40px;
    width: 90px;
}
.footer button:hover{
    opacity: 0.8;
}